Waterpipe smoking is an ancient method of tobacco smoking practiced worldwide. There is a common belief that waterpipe smoking is a safer alternative to cigarette, but many studies showed that some toxicants were associated with cancer risk, significantly higher in waterpipe smoking. Thus, this study aimed to evaluate the status of waterpipe smoker's buccal cells and its cancer risk using the buccal micronucleus cytome test. Forty waterpipe smokers (noncigarette smokers) were recruited and paired by gender, age and alcoholic habits with 40 control subjects. One-thousand cells from each individual were analysed and the number of pyknotic cells (PYC), karyolitic cells (KYL), karyorrhetic cells (KHC), condensed chromatin (CC), binucleated cells (BN), basal cells (BC), nuclear buds (NBUD) and differentiated cells (DIFF) were counted. Additionally, 2000 differentiated cells were analysed counting micronucleated cells (MNi) and nuclear buds. We observed an increasing < 0.05 in all waterpipe smoker's cell parameters, except DIFF (fold-decrease). Only CC showed no differences between groups. The interference in the cell cycle plus DNA damage observed in this study could be responsible for the high number of damaged cells and in death process, showing the importance of our study and the high risk in waterpipe smoking.

Gas station attendants are potentially exposed to carcinogenic substances. This study aimed to evaluate chronic occupational exposed gas station attendant's according to genetic parameters and its relationship with cancer predisposition. Forty gas station attendants were recruited and paired with 40 control subjects. Thousand cells from each subject were analyzed counting the number of pyknotic (PYC), karyolitic (KYL), karyorrhetic (KHC), condensed chromatin (CC), binucleated (BN), basal cells (BC), Nuclear buds (Nbud), and differentiated cells (DIFF). More 2.000 differentiated cells were analyzed counting micronucleated (MNi) and nuclear buds (NBud). We observed a statistical increase in BC and decrease in DIFF (p < 0.05). PYC, CC, KYL, MN, NBud were statistically increased (p < 0.05). All in all, our data showed elevated DNA damage, chromosomal instability, and cell cycle disturbing in our group of gas station attendants. It is a clear risk for their health in future and could be classified as a cancer predisposition.

The glutathione S-transferase mu (GSTM1) gene which acts during phase II of xenobiotic metabolism is polymorphic in the population, being absent in about 30-50% of individuals depending on the ethnic group from which they come. Epidemiological studies suggest that individuals who are homozygous null at the GSTM1 locus may have an increased risk of developing various types of neoplastic disease. We used the polymerase chain reaction (PCR) to estimate the frequency of GSTM1 in 176 healthy individuals from the north of Paraná (Brazilian state), the null genotype being detected in 48.86% of these individuals. The Student's t-test was used to evaluate the frequency of the glutathione S-transferase null genotype in relation to age, gender and smoking habit and no significant differences were found. In our sample there were 142 individuals of Caucasian origin, of which 47.88% had the null genotype. When applied to the Caucasian group only (n = 142) the Student's t-test again showed no significant differences between the frequency of the GSTM1 null genotype and age, gender and smoking habit.

This study evaluated the mutagenic effects of two herbicides: Clorimurom Nortox Ò and Imazaquim Ultra Nortox Ò widely used on soybean crops in Brazil. As a test system, Allium cepa assay was used, which analyzes the frequency of micronuclei (MN), chromosomal aberrations (CA) and the mitotic index (MI). Four concentrations of each herbicide (50, 75, 100 and 125 %) were tested in triplicate using distilled water (negative control) and methyl methanesulfonate (positive control) as controls. Three experimental repetitions were realized. Clorimurom Nortox Ò showed a significantly lower MI than the negative control for the concentrations of 75, 100 and 125 %, but the CA was significantly increased at all concentrations. There was no recovery for CA or MI. The 125 % concentration of Imazaquim Ultra Nortox Ò was cytotoxic and also exerted an effect on the other parameters. The concentration of 100 % showed a statistically increased MN and there was no recovery, while the 75 % concentration significantly affected CA, with recovery observed. The two herbicides showed mutagenic damage in Allium cepa cells, which implies a careful handling of these products, to minimize the risk of human and environmental contamination.

Increasing industrialization and urbanization has deteriorated water quality around the world. Nowadays, evaluation of the effects of chemical compounds using bioassays is a critical step in the hazard identification assessment. Thus, this work aimed to determine the genetic damage caused by different types of anthropogenic contamination in a river´s water in Brazil. Two points (P1 and P2) and two periods (referred as direct and indirect anthropogenic contamination) were evaluated in Allium cepa roots. MI was increased (p < 0.05) in both points in the indirect anthropogenic contamination and decreased in the indirect anthropogenic contamination periods. Moreover, parameters as DNA instability (CA and MN) were observed in both periods indicating substances in the water with mutagenic, genotoxic, and cytotoxic potential. Interestingly, a 20-fold increase in CA frequencies were observed in P1 and P2 in the second collection period (direct anthropogenic contamination) (p < 0.05). In conclusion, our data indicated that anthropogenic activities in the area contributed to contaminate this water source. Moreover, direct anthropogenic contamination maximized the damage, posing a possible hazard to population health.